The present invention relates to photovoltaic cells and more particularly to selenium photovoltaic cells having higher quantum efficiencies.
Known selenium photovoltaic cells comprise a base electrode, a crystalline selenium P-type semiconductive layer, an N-type semiconductive layer, a heterojunction between the two semiconductive layers and a current collecting electrode consisting of an N.sup.+ electrode and a metal grid for collecting current while permitting light to impinge and to be adsorbed by the N-type layer, P-type layer and the junction and to generate ultimately an electric current. Most selenium photovoltaic cells of the type described have sunlight conversion efficiencies of about 1% or less. Based on band gap of the material and assuming 100 percent collection efficiency, the estimate of sunlight conversion efficiencies varies between 10-20%. But, taking into account other realistic factors involving collection efficiencies, the experimental value of 1% has been said to be all that can be expected for these cells.